Avalanche Advisory

Turnagain Area Avalanche Advisory
Wednesday, January 8th 2014 7:00 am by Graham Predeger
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger today remains at CONSIDERABLE above treeline where the potential exists to initiate large slab avalanches 2-3’ deep.  An avalanche triggered today has the potential to propagate across entire slopes in surprising and unpredictable ways.  Cautious route finding and conservative decision-making will again be essential elements to a fun, safe day in the backcountry.

Below treeline the danger remains MODERATE due to the continued, around the clock above freezing temperatures and weak snow found near the base of the snowpack.

 Show the Complete North American Avalanche Danger Scale
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Special Announcement

For anyone who has taken an Avalanche Level 2 course and interested in a refresher check out the Alaska Avalanche School’s “Level 2 refresher/Observer Workshop”. The course will be a lot of fun and taught by CNFAIC’s Wendy Wagner and AAS’s Eeva Latosuo.

Avalanche Problem 1

We haven’t heard of any new avalanche activity since Sunday, when a substantial natural avalanche cycle occurred in addition to a second-hand report of snowmachine-triggered avalanche activity near Seattle ridge.  This most recent cycle has a common theme in the fact that all of these avalanches have been quite large, propagating across entire slopes with faceted snow near the ground proving the common and persistent weak layer. Recent results from the snowpit show these weak layers have been slow to gain strength as Fitz’s video here points out.  This is a great example of the persistent slab problem that has dominated our primary concern over much of the last three weeks.

As few people have been venturing into the backcountry since the Jan. 5th storm, our information is limited.  What information we do have, points toward a snowpack hanging in the balance with a poor structure, moderate strength and high energy.  In a nutshell this means that if a fracture is initiated on or below a slope steep enough to avalanche (> 35 degrees) there is good potential that the crack will propagate far and wide, creating a large and unmanageable avalanche.  Likely trigger points include thin spots in the slab or near rocks and trees mid-slope.

Maintain astute situational awareness and be mindful of any obvious signs of instability if you travel into the backcountry today.  Conservative terrain selection and proper travel protocol will be key.

In areas below treeline where the surface snow is still wet, exists a very poor snowpack structure with free water percolating throughout.  Once overnight temperatures maintain below the freezing mark, this lower elevation snowpack will ‘lock-up’ and we’ll likely see Low danger in this elevation band.

Mountain Weather

Southeast flow continued yesterday ushering in warm temperatures and intermittent bands of rain through the eastern Turnagain arm region with no measurable snow accumulation to speak of.  Winds have been light to moderate predominantly from the East and temperatures remained in the 20’s at ridgetop locations and mid-30’s at 1000 feet.

Today looks to be the start of a gradual cool down with temperatures moderating back to near normal values by the weekend.  Cloudy skies and 28-33 degrees should usher in 2-3” of snow above 1000 feet today with slightly warmer temperatures and a rain/ snow mix at sea level.  Winds will be out of the East at 15-25 mph and look to decrease to single digits from the North by tonight.

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Winter snowmachine use open/closed status and riding conditions updates

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Oct 05, 2019 )

Glacier District
Johnson Pass: ClosedClosed
Placer River: ClosedClosed
Skookum Drainage: ClosedClosed
Turnagain Pass: ClosedClosed
Twentymile: ClosedClosed
Seward District
Carter Lake: ClosedClosed
Lost Lake Trail: ClosedClosed
Primrose Trail: ClosedClosed
Resurrection Pass Trail: ClosedClosed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor: ClosedClosed
South Fork Snow River Corridor: ClosedClosed
Summit Lake: ClosedClosed

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The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.

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